1. Field of the Invention
The present disclosure relates to a novel recombinant viral construct. More particularly, the present disclosure relates to a recombinant viral construct and its uses in producing multiple antigenic proteins required for manufacturing a multi-subunit (e.g., a bi-subunit) vaccine.
2. Description of Related Art
Classical swine fever (CSF) is a contagious and often fatal disease of swine, characterized by fever, hemorrhages, ataxia and immunosuppression. The causative agent is classical swine fever virus (CSFV), a member of the genus Pestivirus of the family Flaviviridae. In many countries, the virus is not endemic, but outbreaks of CSF occur periodically, and may cause large economic losses. Consequently, it is necessary to develop efficient vaccines against CSFV so as to protect pigs against clinical signs of CSF and possible spread of CSFV. A vaccine directed to the structure glycoprotein E2 of CSFV has the advantageous protecting effect on pigs and is known to induce a neutralizing antibody response in pigs.
Post-weaning multi-systemic wasting syndrome (PMWS) is another contagious disease affecting pigs worldwide. This syndrome causes considerable economic losses due to high mortality rates and reduced feed conversion efficiency in weaning and fattening pigs. Porcine circovirus type 2 (PCV2), belonging to the genus Circovirus of the family of Circoviridae, is regarded as the etiological agent of PMWS. Various PCV2 vaccines have been shown to be effective against the development of PMWS, and their use resulted in a significant improvement of nursery and mortality rates of vaccinated farms. Among the known PCV2 vaccines, vaccines directed to open reading frame-2 (ORF-2), which is a major immunogenic protein produced by PCV2, exhibit superior protection effect on pigs due to the production of the PCV2-specific neutralizing antibodies.
As described above, though there are vaccines directed to either CSFV or PCV2, yet most of them are mono-subunit vaccines, meaning each vaccine contains just one type of antigenic protein, either CSFV or PCV2 antigen. Such mono-subunit vaccine can only protect the animal from one type of virus, and thus limiting its protecting spectrum and efficacy.
Accordingly, there exists in the related art a need of a multi-subunit vaccine, which encompasses more than one antigens so as to protect porcine from various viral infections.